1. Field of the Invention
The present invention relates to a memory circuit in which the current which may be supplied by voltage generators is settable, and to a method for manufacturing and a method for operating the same.
2. Description of the Related Art
High-speed memory devices (SDRAM) require several on-chip voltage generators for generating different voltages and operating voltages, respectively (VINT, VBLH, VPP etc.) from a supply voltage supplied from the outside. The currents drawn off from the voltage generators by downstream loads are strongly dependent on the clock frequency. The performance features and the number of voltage generators are implemented to guarantee worst case currents also with a maximum clock frequency of the memory circuit. If the memory circuit is operated below or far below its maximum clock frequency, as it is for example regularly the case with server applications, the number of voltage generators is unnecessarily high. As on the other hand the inherent current consumption of the voltage generators is only little or not dependent on the power they give off to downstream circuits, with clock frequencies below the maximum clock frequency also the current consumption or the current reception or the power reception, respectively, of the voltage generators is not optimum but unnecessarily high. As the inherent current consumption of the voltage generators typically represents two thirds of the overall current consumption of the memory circuit, it has a significant technical and economic importance, as the overall current consumption and its minimization with server applications, respectively, will be more and more important in the future.